ndb/include/kernel/signaldata/ArbitSignalData.hpp:
  new arbitrator behaviour for >=3-way: < 1/2 nodes can survive
ndb/src/common/debugger/EventLogger.cpp:
  new arbitrator behaviour for >=3-way: < 1/2 nodes can survive
ndb/src/kernel/blocks/qmgr/QmgrMain.cpp:
  new arbitrator behaviour for >=3-way: < 1/2 nodes can survive